1. Field of the Invention
The present invention relates to the field of display technology, and in particular to a method for growing graphene on a surface of a gate electrode and a method for growing graphene on a surface of a source/drain electrode.
2. The Related Arts
In the field of display technology, flat panel displays, such as a liquid crystal display (LCD) and an organic light-emitting diode (OLED), have gradually taken the place of a cathode ray tube (CRT) display device and are widely used in liquid crystal televisions, mobile phones, personal digital assistants, digital cameras, computer displays, and notebook computer screens.
A display panel is an important constituent component of the LCD and OLED. The display panel of the LED and the display panel of the OLED both comprise a thin-film transistor (TFT) array substrate. Taking an LCD display panel as an example, it is made up of a TFT array substrate, a color filter (CF) substrate, and a liquid crystal layer interposed between the two substrates and the operation thereof is that a driving voltage is applied to the TFT array substrate and the CF substrate to control the liquid crystal molecules of the liquid crystal layer to rotate for refracting out light emitting from a backlight module to generate an image.
With continuous progress of the semiconductor display technology, display panel are required for increasingly heightened conductive performance for electrode wires on a TFT substrate array and the electrodes of a TFT. Particularly, in high-definition products, to increase aperture ratio, the width of electrode wires must be reduced provided the conductive performance can be maintained. In a large-sized product, to maintain the refreshing frequency of images, the electrical resistance of the electrode wires must be reduced. Since copper (Cu) materials have better electrical conductivity, Cu-based processes have been gradually introduced to the manufacturing of large-sized TFT-LCDs, in which the gate electrode and source/drain electrode are both formed of the Cu materials. In the conventional copper processes, to serve as the gate electrode and the source/drain electrode, copper must often be exposed for the performance of the subsequent processes and would be readily susceptible to oxidization in the subsequent high-temperature and high-humidity processes that leads to a non-conductive isolation layer on the surface of the copper thereby affecting the electrical performance of the entire TFT device. Thus, it is important to cover the surface of the copper with a high conductivity isolation layer to prevent the occurrence of the above-discussed problems.
Graphene is a single layer of carbon atoms having high electrical conductivity and also showing excellent mechanical property. Researches have proven a uniform and compact graphene layer can be formed on a surface of copper through vapor deposition processes. Since the single layer of graphene has excellent property of blocking moisture, it is can be used to prevent water and oxygen from contacting copper and protect copper from being oxidized. In a chemical vapor deposition (CVF) or plasma enhanced chemical vapor deposition (PECVD) process, microwave or radio frequency is used to ionize a gas that contains atoms for constructing a film for generating plasma in a local area. Since the plasma has extremely high chemical activity, reaction may readily occur to thereby deposit a desired film on a substrate. To allow the chemical reaction to occur at a relatively low temperature, the reaction is enhanced by means of the activity of the plasma. Such a chemical vapor deposition process is referred to as plasma enhanced chemical vapor deposition.